Costs of antidepressant medications associated with inadequate treatment.

Objective: To determine the costs of antidepressant medications used during inadequate treatment.
Study Design: Retrospective database analysis of pharmacy claims made by patients who were treated under routine clinical conditions from July 1, 1999, through September 30, 2002.
Patients and Methods: Our participants included 21,632 patients enrolled in a commercial HMO who had a primary care physician associated with our healthcare system. Patients never receiving at least a minimum likely effective antidepressant dose for at least 90 days were defined as having inadequate treatment. This study calculated the costs of antidepressants involved with inadequate treatment at the level of the patient and the medication trial.
Results: A majority of patients (51%) received inadequate treatment. Of overall antidepressant costs, 16% were incurred during trials for patients never adequately treated. The majority of inadequate trials were short and unlikely to have been effective. Most patients (64%) had only a single trial of antidepressants. Venlafaxine, fluoxetine, and sertraline had significantly lower first-trial inadequacy rates compared with the most commonly prescribed agent, citalopram.
Conclusions: Improved patient care quality and lower antidepressant costs could result if clinicians and healthcare systems focus on reducing short trial rates. Initiating treatment with agents least likely to be discontinued prematurely may be helpful.